1. Field of the Invention
This invention relates to systems enabling the remote detection and identification of objects.
2. Description of the Prior Art
Numerous systems utilizing some form of electromagnetically responsive tag or market affixable to an object to be detected and/or identified are known in the art. Such tags are known to include ferromagnetic materials wherein the magnetic field resulting from the magnetization of the material is directly sensed or wherein the effect of the material on an external field is sensed. See, for example, U.S. Pat. Nos. 3,292,808 (Trikilis) and 3,665,449 (Elder and Wright). Tags are also known to include a variety of electrical circuits which, if active, i.e., containing an internal source of power, may produce an electromagnetic field which is remotely sensible. See, for example, U.S. Pat. Nos. 3,582,931 (Nawrocki) and 3,493,955 (Minasy). Similarly, passive tags, i.e., those not having an internal source of power and which are thus incapable of directly producing an electromagnetic field, are capable of responding to an external electromagnetic field in a manner enabling remote electrical detection. Typically, one such general type of passive electrical circuit comprises some form of a tuned inductive-capacitive circuit such that when stimulated by an external electromagnetic field the resonant frequency of the tuned circuit can be detected. Various schemes for so stimulating and detecting LC resonant tags are, for example, set forth in U.S. Pat. Nos. 2,693,525 (Kendall), 2,910,579 (Jones and Currie), 3,299,424 (Vinding), 3,406,391 (LeVon), 3,624,631 (Chomet), 3,713,102 (Martin) and 3,740,742 (Thompson).
In such prior art identification and/or detection systems, the manner of attachment of the tag to the object to be identified and/or detected has been somewhat incidental. Such systems have required that theobject be directly handled in order to affix the tag to the object such as by mechanical fasteners, adhesives, insertion of the tag into the object and the like.
Systems are also known wherein materials such as biologically active chemicals have been remotely delivered to objects via some type of projectile containing the material. Thus, for example, animals may be anethestized via a syringe dart or bullet filled with the appropriate anethetic. The latter method of application is disclosed in U.S. Pat. Nos. 979,993 and 3,616,758.